The occurrence of undesirable vegetation, e.g., weeds, is a constant problem facing farmers in crops, pastures, and other settings. Weeds compete with crops and negatively impact crop yield. The use of chemical herbicides is an important tool in controlling undesirable vegetation. There remains a need for chemical compositions and weed-control methods that offer a broad spectrum of weed control, selectivity, minimal crop damage, storage stability, ease of handling, higher activity against weeds, and/or a means to address herbicide-tolerance that develops with respect to herbicides currently in use.